Dual mode power amplifier control interface with a multi-mode general purpose input/output interface

ABSTRACT

In accordance with some embodiments, the present disclosure relates to a dual mode control interface that can be used to provide both a radio frequency front end (RFFE) serial interface and a two-mode general purpose input/output (GPIO) interface within a single digital control interface die. In certain embodiments, the dual mode control interface, or digital control interface, can communicate with a power amplifier. Further, the dual mode control interface can be used to set the mode of the power amplifier.

RELATED APPLICATIONS

This disclosure claims priority to U.S. application Ser. No. 13/658,488filed Oct. 23, 2012 and entitled “DUAL MODE POWER AMPLIFIER CONTROLINTERFACE WITH A TWO-MODE GENERAL PURPOSE INPUT/OUTPUT INTERFACE,” andwhich claims priority to U.S. Provisional Application No. 61/550,856filed Oct. 24, 2011 and entitled “DUAL MODE POWER AMPLIFIER CONTROLINTERFACE”, and to U.S. Provisional Application No. 61/589,753 filedJan. 23, 2012 and entitled “DUAL MODE POWER AMPLIFIER CONTROLINTERFACE.” The disclosures of each of the above applications are herebyexpressly incorporated by reference herein in their entirety. Further,this disclosure relates to U.S. application Ser. No. 13/658,522 filed onOct. 23, 2012 and entitled “DUAL MODE POWER AMPLIFIER CONTROL INTERFACEWITH A THREE-MODE GENERAL PURPOSE INPUT/OUTPUT INTERFACE,” thedisclosure of which is expressly incorporated by reference herein in itsentirety.

TECHNICAL FIELD

The present disclosure relates generally to power amplifiers. Morespecifically, the present disclosure relates to a dual mode digitalcontrol interface for power amplifiers.

BACKGROUND

A number of electronic devices, including wireless devices, may have oneor more components that are controlled or set by a front-end component.For example, a power amplifier may be set or configured by a poweramplifier controller. In some cases, the power amplifier controller mayitself be controlled or configured by another interface component basedon the state of the device.

Often, various components within a device will be created by differentorganizations. To facilitate interoperability between components, whichmay be designed by different organizations, standards are often adoptedfor different types of devices and components. As technology advances,standards may change or new standards may be adopted. In some cases, thenewer standards are not compatible with the older standards.

SUMMARY

In accordance with some embodiments, the present disclosure relates to adual mode control interface that can be used to provide both a radiofrequency front end (RFFE) serial interface and a general purposeinput/output (GPIO) interface within a single digital control interfacedie. In certain embodiments, the dual mode control interface, or digitalcontrol interface, can communicate with a power amplifier. Further, thedual mode control interface can be used to set the mode of the poweramplifier.

In accordance with certain embodiments, the dual mode control interfaceincludes a RFFE core configured to provide a RFFE serial interface.Further, the dual mode control interface includes a voltage input/output(VIO) pin configured to receive a VIO signal. This VIO signal determineswhether an operating mode of the RFFE core is set to one of an activestate and an inactive state. When the RFFE core is set to the inactivestate, the dual mode control interface is configured to provide ageneral purpose input/output (GPIO) interface In addition, the dual modecontrol interface includes a combinational logic block configured toprovide an enable signal and a mode signal to an enable level shifterand a mode level shifter, respectively. Moreover, the dual mode controlinterface includes a power on reset configured to select the enablesignal and the mode signal to provide to the enable level shifter andthe mode level shifter, respectively, based on the VIO signal.

For some implementations, the dual mode interface includes a clock/modepin configured to provide a clock signal to the RFFE core when the RFFEcore is set to an active state and a mode signal to the combinationallogic block when the RFFE core is set to an inactive state. In addition,the dual mode interface includes a data/enable pin configured to providea data signal to the RFFE core when the RFFE core is set to an activestate and an enable signal to the combinational logic block when theRFFE core is set to an inactive state.

In some variations, the data/enable pin is further configured to providean address signal to the RFFE core, the address signal associated with aregister of the RFFE core.

In some embodiments, the dual mode interface includes a plurality oflevel shifters. Each level shifter of the plurality of level shiftersmay be configured to receive a register signal from the RFFE core. Theregister signal can be associated with a value stored in one of aplurality of registers associated with the RFFE core.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the drawings, reference numbers are re-used to indicatecorrespondence between referenced elements. The drawings are provided toillustrate embodiments of the inventive subject matter described hereinand not to limit the scope thereof.

FIG. 1 illustrates an embodiment of a wireless device in accordance withaspects of the present disclosure.

FIG. 2 illustrates an embodiment of a digital control interface inaccordance with aspects of the present disclosure.

FIG. 3 illustrates an embodiment of a level shifter in accordance withaspects of the present disclosure.

FIG. 4 presents a flowchart of a process for operation of a digitalcontrol interface in accordance with aspects of the present disclosure.

FIG. 5 illustrates an embodiment of a wireless device in accordance withaspects of the present disclosure.

FIG. 6 illustrates an embodiment of a digital control interface inaccordance with aspects of the present disclosure.

FIG. 7 illustrates an embodiment of a combinational logic block inaccordance with aspects of the present disclosure.

FIG. 8 illustrates an embodiment of a digital control interface inaccordance with aspects of the present disclosure.

FIG. 9 illustrates an embodiment of a combinational logic block inaccordance with aspects of the present disclosure.

DETAILED DESCRIPTION Introduction

When a new standard is introduced, or an existing standard is modified,it is often necessary to introduce new components or modify existingcomponents to take advantage of the new or updated standards. Forexample, the adoption of the MIPI® RF Front End (RFFE) standard serialinterface for supporting multiple configuration modes within a module,such as a power amplifier module, may mean that device manufacturers whowish to support the new standard may need to use a new front endcomponent that supports the RFFE standard. Manufacturers of the frontend components who have customers using the RFFE standard and customersusing a different standard, such as the General Purpose Input/Output(GPIO) interface must manufacture two separate components. This can becostly because, for example, more time and human resources must beexpended to produce both types of front end devices.

Further, device manufacturers who wish to support both standards mayoften be required to redesign their products to fit two or morecomponents to support the standards. Not only may this require morephysical space, but it may also result in greater power consumptionbecause, for example, the multiple interface components may each consumepower.

Advantageously, embodiments of the present disclosure provide a systemand method for implementing multiple standards in a single die withoutincreasing the size of the die, or the number of pins required tosupport the front end interfaces. Further, in some embodiments, powerconsumption is not increased compared to devices that use componentsthat implement a single interface standard. Moreover, embodiments of thepresent disclosure provide a single interface component, or die, tosupport the RFFE serial interface, the GPIO interface, or bothinterfaces without any modifications to existing devices. In certainimplementations, the size and the pin count of single component may bekept the same as a die that implements only one of the RFFE interfaceand the GPIO interface.

In certain embodiments, the interface component, or digital controlinterface, includes a RFFE core that implements the functionality of theMIPI® RFFE serial interface. This RFFE core can be configured to receivepower from a Voltage Input/Output (VIO) pin. In a number ofimplementations, the RFFE core can cease receiving power when not inuse. When the RFFE core is not powered, the digital control interfacecan be configured to use the pins that provide signals to the RFFE coreas a GPIO interface. By using combinational logic, the digital controlinterface can control whether signals associated with the use of theRFFE serial interface or the GPIO interface are provided to, forexample, a power amplifier. Advantageously, in certain embodiments, bymerging the RFFE serial interface and the GPIO interface on a singledie, it is possible for seamless adoption of the RFFE serial standardwithout alienating any manufacturers that are still using the GPIOinterface. More details regarding combining the RFFE serial standard andthe GPIO interface are described herein.

Example Electronic Device

FIG. 1 illustrates an embodiment of a wireless device 100 in accordancewith aspects of the present disclosure. Applications of the presentdisclosure are not limited to wireless devices and can be applied to anytype of electronic device, with or without a power amplifier. Forexample, embodiments can be applied to wired devices, weather sensingdevices, RADAR, SONAR, microwave ovens, and any other device that mightinclude a power amplifier. Further, embodiments of the presentdisclosure can be applied to devices that may include one or morecomponents controlled via a front end interface. For example,embodiments of the present disclosure can be applied to Switch ModePower Supply (SMPS) devices, which can be used for power amplifiersupply regulation, Antenna Switch Modules (ASM), and antenna load tuningmodules, to name a few. Although the present disclosure is not limitedto wireless devices or to controlling power amplifiers, to simplifydiscussion, a number of embodiments will be described with respect tothe wireless device 100 and a power amplifier module 102.

The wireless device 100 can include a power amplifier module 102. Thepower amplifier module 102 can generally include any component or devicethat includes a power amplifier 104 and a power amplifier controller 106for controlling the power amplifier 104. Although not limited as such,controlling the power amplifier 104 generally refers to setting,modifying, or adjusting the amount of power amplification provided bythe power amplifier 104. In some implementations, the power amplifier104 may include the power amplifier controller 106. Further, the poweramplifier module 102 may be a single component that includes thefunctionality of the power amplifier controller 106 and the poweramplifier 104. In other implementations, the wireless device 100 mayinclude the power amplifier 104 and the power amplifier controller 106as separate and distinct components.

Further, the wireless device 100 can include a digital control interface108. In some embodiments, the power amplifier module 102 includes thedigital control interface 108. Generally, the digital control interface108 can include any type of control interface that can support multipletypes of front end interfaces. For example, the illustrated digitalcontrol interface 108 can support both a MIPI® Radio Frequency (RF)Front End (RFFE) serial interface 110 and a General Purpose Input/Output(GPIO) interface 112. In a number of embodiments, the digital controlinterface 108 can support multiple types of front end interfaces suchthat the interfaces can coexist on the same component die withoutrequiring circuit design changes or bonding changes. Further, in someembodiments, the digital control interface 108 can support multiplefront end interfaces without increasing the number of interface pins orconnecting points exposed for use by the wireless device 100.Advantageously, in a number of embodiments, the digital controlinterface 108 can be used with devices that support different interfacestandards without modifying the digital control interface 108. Forexample, the illustrated digital control interface 108 of FIG. 1, can beused with devices that support MIPI® RFFE, GPIO, or a combination of thetwo without modifying the digital control interface 108.

In certain implementations, the digital control interface 108 can serveas an intermediary or a manager between the power amplifier module 102and a signal source that determines or sets the mode of operation of thepower amplifier module 102, the power amplifier controller 106, thepower amplifier 104, or any other component that can be controlled bythe digital control interface 108. The signal source can include anycomponent that is configured to provide signals to the digital controlinterface 108 that can cause the digital control interface 108 todetermine or set the mode of operation of, for example, the poweramplifier module 102. For instance, as illustrated in FIG. 1, the signalsource can be a transceiver 114. Alternatively, or in addition, thesignal source can include a baseband chip 116, a digital signalprocessor (DSP) 118, or any other component that can provide one or moresignals to the digital control interface 108 to cause the digitalcontrol interface 108 to set the mode of operation of the poweramplifier module 102 or the power amplifier 104.

In one example of a scenario of setting the mode of the power amplifier104, the transceiver receives a signal from, for example, the antenna120 or the DSP 118. In response to receiving the signal, the transceiver114 can provide one or more signals to the digital control interface 108associated with setting the mode of operation of the power amplifier104. The digital control interface 108 can determine, based on thereceived signals from the transceiver 114, whether the received signalsare associated with a RFFE serial interface 110 or a GPIO interface 112.The digital control interface 108 can then process the received signalsusing the identified interface (e.g. the RFFE serial interface 110, theGPIO interface 112, or any other interface the digital control interface108 can include). Then, based on the outcome of processing the receivedsignals, the digital control interface 108 can provide mode settingsignals to the power amplifier control 106, which can set the mode ofthe power amplifier 104 based on the mode setting signals.

Generally, the mode settings of the power amplifier 104 correspond tothe rate or quantity of power amplification of a signal, which is thenprovided to components of a device (e.g. the wireless device 100). Thissignal can be provided to power the components or for processing by thecomponents of the wireless device 100. The power amplifier module canreceive power from a power supply 122. The power amplifier module 102can then distribute the power to a number of components included in thewireless device 100 as illustrated by the power distribution bus 124.

The wireless device 100 can include a number of additional components.At least some of these additional components may receive power via thepower distribution bus 124. Further, at least some of the additionalcomponents may communicate with the digital control interface 108 andmay cause the digital control interface 108 to modify the settings ofthe power amplifier module 102. For example, the wireless device 100 caninclude a digital to analog convertor (DAC) 126, a display processor128, a central processor 130, a user interface processor 132, an analogto digital convertor 134, and memory 136.

Further, the components of the wireless device 100 illustrated in FIG. 1are provided as examples. The wireless device 100 may include othercomponents. For example, the wireless device 100 may include an audioprocessor, a gyroscope, or an accelerometer. Moreover, the variousillustrated components may be combined into fewer components, orseparated into additional components. For example, the DAC 126 and theADC 134 can be combined into a single components, and the based bandchip 116 can be combined with the transceiver 114. As another example,the transceiver 114 can be split into a separate receiver andtransmitter.

Example of a Digital Control Interface

FIG. 2 illustrates an embodiment of a digital control interface 200 inaccordance with aspects of the present disclosure. The digital controlinterface 200 includes both a RFFE serial interface and a GPIOinterface. Advantageously, in certain embodiments, the digital controlinterface 200 can be implemented in the same size package with the samenumber of pins as a control interface that includes one of a RFFE serialinterface and a GPIO interface. The ability to combine multipleinterface types within a single chip without expanding the size of thechip is particularly advantageous for applications that use or requiresmall packages, such as applications that may require 3 mm×3 mm modules.

The digital control interface 200 includes an RFFE core 202 that isconfigured to provide the functionality of a MIPI® RFFE serialinterface. Further, the digital control interface 200 includes a numberof input pins: a VIO pin 204, a clock/mode pin 206, and a data/enablepin 208.

The VIO pin 204 is configured to receive a signal indicating whether thedigital control interface 200 should operate as a RFFE serial interface,or a GPIO interface. In the illustrated embodiment, the digital controlinterface 200 operates as a RFFE serial interface when the VIO pin 204receives a logic high signal and operates as a GPIO interface when theVIO pin 204 receives a logic low signal. However, in someimplementations, the digital control interface 200 can be configured tooperate as a RFFE serial interface when the VIO pin 204 receives a logiclow signal and as a GPIO interface when the VIO pin 204 receives a logichigh signal. The logic low signal can be associated with any valuedefined to be low, such as 0 volts, −5 volts, or otherwise. Similarly,the logic high signal can be associated with any value defined to behigh, such as 0 volts, +5 volts, or otherwise. In some implementations,the logic low signal may be associated with connecting the VIO pin 204to ground. Similarly, in some cases, the logic high signal may beassociated with connecting the VIO pin 204 to a voltage source.

In addition to setting the mode of operation for the digital controlinterface 200, the VIO pin 204 can also provide power from a powersource, such as the power supply 122, to the RFFE core 202. Thus, insome embodiments, when the VIO pin 204 is set to logic low, or isgrounded, the RFFE core 202 is not powered and the digital controlinterface 200 is configured to function as a GPIO interface. On theother hand, in some embodiments, when the VIO pin 204 is set to logichigh, or is connected, directly or indirectly, to a power source, theRFFE core 202 is provided with power and the digital control interface200 is configured to function as a RFFE serial interface.

Further, the digital control interface 200 includes a power on reset210, which may be implemented in hardware, software, or a combination ofthe two. The power on reset 210 is configured to facilitate resettingthe RFFE core 202. In some embodiments, the power on reset 210 can serveas an inverted delay function. The inverted delay function is configuredto provide sufficient time for one or more logic blocks and/or one ormore registers associated with the RFFE core 202 to be set to a knowncondition or value when configuring the digital control interface 200 asa RFFE serial interface. Although in some cases the length of time maybe application specific, in other cases the length of time may be basedon characteristics of the hardware design and/or implementation. Forexample, the amount of time required may depend on the clock frequency,the size of the logic components, the type of components connected,directly or indirectly, to the digital control interface 200, etc.Further, setting the logic blocks and/or registers to known values mayoccur when initializing the RFFE core 202 or taking the RFFE core 202out of a reset state.

In some implementations, the power on reset 210 may be configured toprovide a select signal to the combinational logic block 212. Forexample, assume that the digital control interface 200 is configured tooperate as a GPIO interface when the VIO pin 204 receives a logic lowsignal and as a RFFE serial interface when the VIO pin 204 receives alogic high signal. Continuing this example, when the VIO pin 204receives a logic low signal, the select signal provided by the power onreset 210 may cause the combinational logic block 212 to output to theenable level shifter 216 and the mode level shifter 218 the signalsinput to the data/enable pin 208 and the clock/mode pin 206respectively. Alternatively, if the VIO pin 204 receives a logic highsignal, the select signal provided by the power on reset 210 may causethe combinational logic block 212 to output signals provided by the RFFEcore 202 to the enable level shifter 216 and the mode level shifter 218.In certain embodiments, the combinational logic block 212 may delay orotherwise modify the signals received from data/enable pin 208 and theclock/mode pin 206 or the RFFE core 202 before outputting the signals tothe level shifters.

Moreover, in some cases, the power on reset 210 may be configured toplace one or more of the level shifters 214 into a default state. Forexample, the level shifters 214 may be placed into a default or resetstate when the RFFE core 202 is in a reset state. In some designs, thepower on reset 210 may be connected to a default high pin associatedwith each level shifter configured to be high during GPIO interface modeand to a default low pin associated with each level shifter configuredto be low during GPIO interface mode. In some implementations, setting alevel shifter 214 into a default state may cause the level shifter 214to output a value based on a default input signal provided by thedefault pin 220. Although the default pin 220 is illustrated asreceiving a default input signal, in a number of embodiments, thedefault pin 220 is tied to one of a default high and a default lowinput. Thus, in some cases, the default value may be pre-configured,while in other cases, the default value may be variable based onconfiguration or operation. It is possible in some designs that eachlevel shifter 214 may be associated with a different default value orsignal. Alternatively, each level shifter 214 may be associated with thesame default value or signal.

Each of the level shifters 214 may be powered through a Vcc pin 224. Insome implementations, each level shifter 214 may be separately connectedto a power source. Alternatively, a single level shifter 214 may beconnected, directly or indirectly, to a power source, and the remaininglevel shifters 214 may obtain power by a connection to the level shifter214, or other component, that is connected to the power source. Further,the level shifters 216 and 218 may similarly each be connected to apower source, or may be connected to a level shifter or other componentthat can provide power to the level shifters 216 and 218. In certainembodiments, the level shifters 214, 216, and 218 are configured toadjust the voltage level of received signals and to output the modifiedsignals. Although not limited as such, the level shifters 214, 216, and218 may adjust the voltage level of the received signals tosubstantially match the voltage applied at the Vcc pin 224.

Although FIG. 2 illustrates two level shifters 214, the disclosure isnot limited as such. The RFFE core 202 may communicate, directly orindirectly, with one, two, three, or any number of additional levelshifters 214. Further, in some cases, the digital control interface 200includes as many level shifters 214 as the number of registers (notshown) that the RFFE core 202 includes. Each register can provide asignal associated with the value of the register to a correspondinglevel shifter 214. In some cases, there may exist more or less levelshifters 214 than registers. For example, each level shifter 214 may beassociated with two registers. In this example, logic internal to theRFFE core 202 may determine which register's value is provided to thecorresponding level shifter 214. As a second example, the RFFE core 202may include additional registers that are included for internal use bythe RFFE core 202. In this example, not all the registers of the RFFEcore 202 may be associated with a level shifter 214. The level shifters214, 216, and 218 are described in more detail below with respect toFIG. 3.

As previously indicated, the RFFE core 202 may include a set ofregisters (not shown). In certain situations, the set of registers maybe set to unknown values. For example, when the wireless device 100 isfirst powered the set of registers may be set to unknown values. As asecond example, in implementations where the VIO pin 204 serves as boththe power source for the RFFE core 202 and the mode selector betweenRFFE and GPIO mode, the set of registers may be set to unknown valueswhen the digital control interface 200 is first transitioned from a GPIOinterface to a RFFE serial interface. To ensure that the registers areset to known values when the RFFE core 202 is initially powered or takenout of a reset state, the RFFE core 202 can be configured to set thevalue of each of the set of registers to values provided by a set ofstrapped defaults 222. In certain implementations, the strapped defaults222 may be equivalent to the values provided to the default pins 220.

The RFFE core 202 may be configured to receive a clock signal from theclock/mode pin 206. This clock signal may be set to any frequency orsignal shape based on the implementation of the RFFE core 202. In someimplementations, the clock signal may be a square wave with a frequencyof 26 MHz or less. Further, the data interface of the RFFE core 202 maybe bidirectional. Thus, the RFFE core 202 may receive data from thedata/enable pin 208 at the Data In of the RFFE core 202. Similarly, theRFFE core 202 may provide data from the Data Out of the RFFE core 202 tothe data/enable pin 208. As illustrated in FIG. 2 by the buffers 232 and234, both the data input and the data output may be buffered. In someembodiments, the buffers may be tri-state buffers. In someimplementations, the Output Enable of the RFFE core 202 is configured tocontrol the buffers 232 and 234 to enable both the Data Out and the DataIn to share the same line to and from the data/enable pin 208. Thus, insome examples, when reading data from the RFFE core 202, the buffer 232enables data flow, while the buffer 234 prevents data flow, or is set tohigh impedance. Similarly, in some examples, when writing data to theRFFE core 202, the buffer 234 enables data flow, while the buffer 232prevents data flow, or is set to high impedance.

The following are non-limiting examples of use cases for the digitalcontrol interface 200. Other operations and uses are possible inaccordance with the various embodiments described here. In one exampleuse case, a logic low signal is received at the VIO pin 204. This signalmay be received from the transceiver 114, for example. Receiving thelogic low signal causes the digital control interface 200 to operate asa GPIO interface. Thus, in this example, the RFFE core 202 is inactive.Further, the combinational logic block 212 passes the signals receivedat the clock/mode pin 206 and the data/enable pin 208 to the mode levelshifter 218 and the enable level shifter 216 respectively. The levelshifters 216 and 218, upon modifying the voltage level of the signals,provide the signals to the power amplifier controller 106. The poweramplifier controller 106, based on the signals received from the levelshifters 216 and 218, controls the power amplifier 104 to set the levelof amplification of a signal received by the power amplifier 104, suchas a signal provided by the power supply 122 or the transceiver 114. Thepower amplifier controller 106 may also receive signals associated witha default from the level shifters 214. If so, the power amplifiercontroller 106 may ignore the signals from the level shifters 214 or maycontrol the power amplifier 104 based in part on the signals receivedfrom the level shifters 214.

As a second example use case, a logic high signal is received at the VIOpin 204. This signal may be received from a baseband chip 116, forexample. Receiving the logic low signal causes the digital controlinterface 200 to operate as a RFFE serial interface. Thus, in thisexample, the RFFE core 202 is active and the combinational logic block212 passes mode and enable signals received from the RFFE core 202 tothe mode level shifter 218 and the enable level shifter 216respectively. The level shifters 216 and 218, upon modifying the voltagelevel of the signals, provide the signals to the power amplifiercontroller 106. The power amplifier controller 106 may control the poweramplifier 104 based in part on the signals received from the levelshifters 216 and 218. In certain embodiments, the power amplifiercontroller 106 may ignore the signals of the level shifters 216 and 218when the digital control interface 200 is operating as an RFFE serialinterface.

Continuing the second example use case, the RFFE core 202 may receive aclock signal from the clock/mode pin 206 and an address signal from thedata/enable pin 208. Alternatively, or in addition, the RFFE core 202may receive a data signal from the data/enable pin 208. In some cases,the data signal is received after the address signal. Alternatively, thedata signal may be received before the address signal. Further, inembodiments where the digital control interface 200 includes a separateaddress pin (not shown), the RFFE core 202 may receive the addresssignal and the data signal at least partially in parallel.

The RFFE core 202 can use the clock signal to synchronize operation ofone or more components associated with the RFFE core 202. Further, theclock signal can be used to facilitate identifying register addressesand data associated with a signal received from the data/enable pin 208.The RFFE core 202 may use the address signal to identify a registerassociated with the RFFE core 202. The RFFE core 202 may then store atthe register data associated with the data signal. In some embodiments,the RFFE core 202 may modify existing data at the register based on thedata signal. Further, in some cases the signal received at thedata/enable pin 208 may control the RFFE core 202 or cause the RFFE core202 to modify its operation.

In certain embodiments, the RFFE core 202 may provide one or moresignals to the level shifters 214. The signals provided by the RFFE core202 may be associated with the values and/or signals stored at theregisters associated with the RFFE core 202. Further, the level shifters214 may then provide the signals and/or modified versions of the signalsto the power amplifier controller 106. The power amplifier controller106 sets the configuration of the power amplifier 104 based at least inpart on the signals from the level shifters 214, and in some cases,based at least in part on the signals from the mode level shifter 218and/or the enable level shifter 216.

Generally, the signals received at the VIO pin 204, the clock/mode pin206, and the data/enable pin 208 are digital signals. However, in someembodiments, one or more of the received signals may be analog signals.For instance, the signal received at the VIO pin 204 may be an analogsignal. Further, each of the components illustrated in FIG. 2 can beincluded in a single chip or die, such as the digital control interface108. Advantageously, in certain embodiments, including each of thecomponents of the digital control interface 200 in a single die enablesa wireless device, such as the wireless device 100, to have thecapability to use the RFFE serial interface, the GPIO interface, or bothtypes of interfaces without requiring multiple chips. By using a singlechip instead of multiple chips, certain embodiments can reduce powerconsumption and reduce the footprint required by the control interfacefor the power amplifier 104, or any other module that may use a controlinterface.

Example of a Level Shifter

FIG. 3 illustrates an embodiment of a level shifter 300 in accordancewith aspects of the present disclosure. Embodiments of the levelshifters 214, 216, and 218 may be equivalent to or substantiallyequivalent to the level shifter 300. In some implementations, the levelshifters 214, 216, and 218 may differ in design from the level shifter300. However, each of the level shifters is capable of modifying thevoltage of an input signal. In some cases, the voltage of the inputsignal is shifted or modified to match the voltage provided at the Vccpin 224. In other cases, the voltage of the input signal is shifted ormodified within a range between the input voltage and the voltageprovided at the Vcc pin 224.

During operation, the level shifter 300 is capable of receiving an inputsignal at an input 302. This input signal can generally include anysignal that is to have its voltage level modified. Thus, for instance,the input signal can include one or more of the signals describedpreviously with respect to FIG. 2. For example, the input signal can bea signal provided from the RFFE core 202, including from one of theregisters associated with the RFFE core 202. As a second example, theinput signal can be a signal provided by the combinational logic block212.

The input signal received at the input 302 is provided to a latch 304.The latch 304 can include any type of flip-flop. For example, asillustrated in FIG. 3, the latch 304 can be a NAND based RS flip-flop.However, other types of flip-flops are possible. For example, the latch304 can be a NOR based RS flip-flop. In certain embodiments, the latch304 ensures a non-overlapping output from the latch 304. Ensuring anon-overlapping output ensures that each pair of NFET transistors 306are not activated at the same time. In some embodiments, two parallelsignal paths with delay elements can be used to ensure that each pair ofNFET transistors 306 are not activated at the same time.

With some implementations, the latch 304 provides two signals, onesignal from each of the NAND gates (e.g. a set signal and a resetsignal). Each of the signals can be provided to a pair of NFETtransistors 306. The NFET transistors 306 can be activated by thesignals from the latch 304. When activated, the NFET transistors set thestate a cross-coupled pair of PFET transistors 308. The cross-coupledpair of PFET transistors 308 causes the voltage level of the inputsignal to be level shifted. This level shifted signal is then providedat the output 310 to, for example, the power amplifier controller 106 orthe power amplifier 104. In some embodiments, such as when a negativeoutput voltage operation may be desired, the NFET transistors 306 can bePFET transistors and the PFET transistors 308 can be NFET transistors.

In some embodiments, it is possible that a signal is not provided at theinput 302, or that the signal is substantially zero. In suchembodiments, the NFET transistors 306 may be set or activated by adefault signal provided by a default low input 312 and/or a default highinput 314. Although FIG. 3 illustrates two defaults, the default highinput 314 and the default low input 312, in a number of embodiments,only a single default signal is provided to the level shifter 300. If itis desired that the output 310 be high during reset, the default highinput 314 would be configured to provide a signal during reset. Ifinstead it is desired that the level shifter 300 provide a low outputduring reset, the default low input 312 would be configured to provide asignal during reset. The default input that is not configured to set theNFET transistors 306 during reset may be tied to ground, or in certainimplementations, may not exist. In some implementations, the default lowinput 312 and/or the default high input 314 is pre-configured orconnected to a signal generator that provides a pre-determined signal.Alternatively, the default low input 312 and/or the default high input314 may be connected to the power on reset 210. In some embodiments, oneor both of the default inputs 312 and 314 may be optional. For example,in some cases, the enable level shifter 216 and the mode level shifter218 receive a signal at their input.

Example of a Process for Operation of a Digital Control Interface

FIG. 4 presents a flowchart of a process 400 for operation of a digitalcontrol interface 200 in accordance with aspects of the presentdisclosure. The process 400 may be implemented by any type of digitalcontrol interface that is configured to operate as an RFFE serialinterface and as a GPIO interface. For example, the process 400 can beimplemented by the digital control interface 100 and the digital controlinterface 200. Further, the process 400, in some embodiments, can beimplemented by any type of digital control interface that is configuredto operate in different interface modes. Although implementation of theprocess 400 is not limited as such, to simplify discussion, the process400 will be described as being implemented by the digital controlinterface 200.

The process 400 begins when, for example, the digital control interface200 receives signals at the VIO pin 204, the clock/mode pin 206, and thedata/enable pin 208 at block 402. In some embodiments, the signalsreceived at one or more of the clock/mode pin 206 and the data/enablepin 208 may be delayed, may be noise, or may be some known or unknownsignals that are ignored until the digital control interface 200completes an initialization process.

The signal received at the VIO pin 204 is provided to the RFFE core 202at block 404. In some implementations, the signal from the VIO pin 204powers the RFFE core 202. Further, the signal, or lack thereof, from theVIO pin 204 may result in the RFFE core 202 not receiving power. Inaddition to providing the VIO signal to the RFFE core 202, block 404 mayinclude providing the VIO signal to the power on reset 210. In someembodiments, the power on reset 210 may provide the signal from the VIOpin 204 to the combinational logic block 212. Further, the power onreset 210 may delay or otherwise modify the signal from the VIO in 204before providing the delayed or modified signal to the combinationallogic block 212. Similarly, in certain embodiments, the power on reset210 may provide the VIO signal, a delayed version of the VIO signal, ora modified version of the VIO signal to a reset input associated withthe RFFE core 202.

At block 406, the signal received at the clock/mode pin 206 is providedto the combinational logic block 212. Similarly, at block 408, thesignal received at the data/enable pin 208 is provided to thecombinational logic block 212. Further, at block 410, a mode signal froman RFFE mode register associated with the RFFE core 202 is provided tothe combinational logic block 212. Similarly, at block 412, an enablesignal from an RFFE enable register associated with the RFFE core 202 isprovided to the combinational logic block 212. During certain operatingstates, the signals provided at blocks 410 and 412 may be noise or maybe some known or unknown signal that does not affect the operation ofthe digital control interface 200. Further, in some operating states, isit possible for no signal to be provided at blocks 410 and 412. Forexample, in implementations where the RFFE core 202 is not powered, suchas when the digital control interface 200 is operating as a GPIOinterface, it is possible for no signal to be provided at the blocks 410and 412. In some implementations, the blocks 410 and 412 may beoptional.

At decision block 414, the digital control interface 200 determineswhether the VIO signal is logic high. In certain implementations,determining whether the VIO signal is logic high includes configuringthe digital control interface 200 based on the VIO signal. Configuringthe digital control interface 200 includes adjusting the operation ofportions of the digital control interface 200 as well as adjusting theflow of signals within the digital control interface 200 as is describedfurther with respect to the remaining blocks of FIG. 4.

If at decision block 414 the VIO signal is not logic high, the digitalcontrol interface 200 operates as a GPIO interface and the process 400proceeds to block 416 where the RFFE core 202 is placed into a resetmode. This reset mode may be an active reset where the RFFE core 202maintains known, or unknown, values in its registers and outputs valuesfrom its output ports. Alternatively, if, for example, the logic low VIOsignal is provided by grounding the VIO pin 204 or by disconnecting theVIO pin 204 from a power source, the RFFE core 202 ceases to be poweredwhile in the reset mode.

At block 418, the signal from the clock/mode pin 206, provided at theblock 406, is provided to the mode level shifter 218. Similarly, atblock 420, the signal from the data/enable pin 208, provided at theblock 408, is provided to the enable level shifter 216. In certainimplementations, the signals provided to the level shifters at blocks418 and 420 may be based on, or selected based on the signal provided bythe power on reset 210 to the combinational logic block 212. Moreover,in some cases, the signals provided to the level shifters 218 and 216 atthe blocks 418 and 420 respectively may be delayed or modified by thecombinational logic block 212 before the signals are provided to thelevel shifters 218 and 216.

At block 422, the digital control interface 200 maintains default valuesat the RFFE register level shifts 214. These default values are providedvia the default pin 220. In a number of implementations, the defaultvalues may be application-specific. Further, the default values may bepreconfigured and/or hard-coded. Alternatively, the default values maybe generated or determined based on the operation of the digital controlinterface 200 and/or one of more of the components associated with thewireless device 100. In certain embodiments, the block 422 may beoptional.

If at decision block 414 the VIO signal is logic high, the digitalcontrol interface 200 operates as an RFFE serial interface and theprocess 400 proceeds to block 424 where the RFFE core 202 is taken outof a reset mode. In some cases, the process 400 is performed when thewireless device 100 is first powered or initialized after a time periodof not being powered. In such cases, the block 424 may be performed aspart of the initialization of the digital control interface 200.Further, the block 424 may include initializing the RFFE core 202instead of, or in addition to, taking the RFFE core 202 out of a resetmode. Removing the RFFE core 202 from reset mode may be a delayedprocess to provide sufficient time for one or more registers, signals,and/or components associated with the RFFE core 202 to stabilize and/orbe initialized. This delay process may be controlled and/or implementedby the power on reset 210. In some embodiments, the block 424 may beoptional.

At block 426, the process 400 includes configuring internal registers(not shown) associated with the RFFE core 202 to a set of defaultvalues. These default values may be provided by the strapped defaults222. Alternatively, the default values may be determined based oninternal logic associated with the RFFE core 202 and set in response tosignals received from one or more of the VIO pin 204, the clock/mode pin206, and the data/enable pin 208.

At block 428, a mode signal from the RFFE core 202 is provided to themode level shifter 218. This mode signal may be associated or obtainedfrom a mode register of the RFFE core 202. Alternatively, or inaddition, the mode signal may be based, at least in part, on one or moreof the following: a signal received from the clock/mode pin 206, asignal received from the data/enable pin 208, a value based on thestrapped defaults 222, and logic internal to the RFFE core 202.

Further, at block 430, an enable signal from the RFFE core 202 isprovided to the enable level shifter 216. This enable signal may beassociated or obtained from an enable register of the RFFE core 202.Alternatively, or in addition, the enable signal may be based, at leastin part, on one or more of the following: a signal received from theclock/mode pin 206, a signal received from the data/enable pin 208, avalue based on the strapped defaults 222, and logic internal to the RFFEcore 202.

In certain implementations, the signals provided to the level shiftersat blocks 428 and 430 may be based on, or selected based on the signalprovided by the power on reset 210 to the combinational logic block 212.Moreover, in some cases, the signals provided to the level shifters 218and 216 at the blocks 428 and 430 respectively may be delayed ormodified by the combinational logic block 212 before the signals areprovided to the level shifters 218 and 216.

At block 432, the process 400 includes providing RFFE register values,or signals associated with RFFE registers, to the RFFE level shifters214. The RFFE register values are from registers associated with theRFFE core 202. Although in some cases these registers may include theregisters described above with respect to the blocks 428 and 430,generally the registers of block 432 are different registers. Further,the values provided by the registers are used to set or to specify themode of the power amplifier 104. While in GPIO interface mode, thedigital control interface 200 may be limited to specifying two modes,such as high and low, associated with two voltage values and/or twolevels of power amplification. In embodiments where the digital controlinterface includes additional pins, the digital control interface 200may be capable of specifying additional modes while in GPIO mode. Whilein RFFE serial interface mode, the digital control interface 200 may setor specify different modes for the power amplifier 104 based on valuesclocked in to the RFFE core 202, values stored in registers associatedwith the RFFE core 202, or a combination of the two.

Regardless of whether the VIO signal is logic high or logic low, theoutput of the mode level shifter 218 is provided to the power amplifier104 at block 434. Similarly, regardless of whether the VIO signal islogic high or logic low, the output of the enable level shifter 216 isprovided to the power amplifier 104 at block 434. In certainembodiments, the outputs of the mode level shifter 218 and the enablelevel shifter 216 are provided to the power amplifier controller 106.The power amplifier controller 106 may then configure the poweramplifier 104 based, at least in part, on the received signals from themode level shifter 218 and the enable level shifter 216.

At block 438, the outputs of the RFFE level shifters 214 are provided tothe power amplifier 104. Alternatively, the outputs of the RFFE levelshifters 214 may be provided to the power amplifier controller 106,which may then configure the power amplifier 104 based, at least inpart, on the received signals from the RFFE level shifters 214. When thedigital control interface 200 is operating as a GPIO interface, theoutput of the RFFE level shifters 214 may be based, at least in part, onthe default values or signals received at the default pins 220. Incontrast, when the digital control interface 200 is operating as a RFFEserial interface, the output of the RFFE level shifters 214 may bebased, at least in part, on values or signals received from the RFFEcore 202, including values stored in registers associated with the RFFEcore 202. In some embodiments, one or more of the block 434, 436, and438 may be optional. For example, when the digital control interface 200is operating as a GPIO interface, the level shifters 214 may not providevalues to the power amplifier 104, or the power amplifier controller106.

Second Example of an Electronic Device

FIG. 5 illustrates an embodiment of a wireless device 500 in accordancewith aspects of the present disclosure. In some implementations, some orall of the embodiments described above with respect to the wirelessdevice 100 may apply to the wireless device 500.

The wireless device 500 can include a power amplifier module 502. Thepower amplifier module 502 can generally include any component or devicethat includes a power amplifier 504, a power amplifier controller 506for controlling the power amplifier 504, a digital control interface508, and a mode selector 540. Although not limited as such, controllingthe power amplifier 504 generally refers to setting, modifying, oradjusting the amount of power amplification provided by the poweramplifier 504.

As with the digital control interface 108, the digital control interface508 can include any type of control interface that can support multipletypes of interfaces for controlling the power amplifier 504 and/or forconfiguring the power amplifier controller 506 to control the poweramplifier 504. For example, the digital control interface 508 caninclude a serial interface 510 and a GPIO interface 512. The serialinterface 510 can include any type of serial interface. For example, theserial interface can be a RFFE serial interface (e.g., the MIPI® RFFEserial interface), a Serial Peripheral Interface (SPI) Bus, a 3-wireserial bus, or an I²C bus, to name a few. In some implementations, someor all of the embodiments described above with respect to the digitalcontrol interface 108 may apply to the digital control interface 508.

In a number of embodiments, the digital control interface 508 caninclude multiple interface types on the same component die withoutrequiring circuit design changes or bonding changes to existingcomponent die configurations (e.g., existing power amplifiers, existingpower amplifier modules, existing transceivers, or other components thatmay provide control signals to a digital control interface or that mayreceive control signals from a digital control interface). Further, insome embodiments, the digital control interface 508 can support multipleinterfaces without increasing the number of interface connections (e.g.,pins, leads, wires, Ball Grid Arrays, etc.) exposed for use by thewireless device 500 or the power amplifier module 508. Advantageously,in a number of embodiments, the digital control interface 508 can beused with devices that support different interface standards withoutmodifying the digital control interface 508. For example, theillustrated digital control interface 508 of FIG. 5, can be used withdevices that support a serial interface, a GPIO interface, or acombination of the two without modifying the digital control interface108. In some cases, the digital control interface 508 can switch betweendifferent interface types during operation.

The mode selector 540 can include any device or component configured toselect the mode of operation of the digital control interface 508.Selecting the mode of operation of the digital control interface 508 caninclude selecting the type of interface the digital control interface508 uses to communicate with the power amplifier controller 506. Forexample, the mode selector 540 can select or configure the digitalcontrol interface 508 to act as a serial interface or a GPIO interface.This selection may be based on a signal received from the antenna 520,the transceiver 514, a baseband chip 516, or any other signal sourcethat may provide a signal that can be used to select the interface typeor to determine the interface type to select from the availableinterface types of the digital control interface 508.

Further, in certain implementations, the digital control interface 508can set the mode of operation of the power amplifier 504, eitherdirectly or via the power amplifier controller 506, based on one or moresignals received from the signal source. In certain embodiments, thedigital control interface 508 receives the one or more signals thatcause the digital controller interface 508 to set the mode of operationof the power amplifier 504 from, for example, the antenna 520, thetransceiver 514, the baseband 516, or the DSP 518 while receiving thesignal that selects the operative interface type of the digital controlinterface 508 from the mode selector 540. Alternatively, the digitalcontrol interface 508 may receive the one or more signals that cause thedigital control interface 508 to set the mode of operation of the poweramplifier 504 and the signal that selects the operative interface typeof the digital control interface 508 from the mode selector 540. Themode selector 540 may receive some or all of the signals from, forexample, the antenna 520, the transceiver 514, the baseband 516, or theDSP 518. Alternatively, or in addition, the mode selector 540 maygenerate some or all of the signals provided to the digital controlinterface 508 based on one or more signals received from, for example,the antenna 520, the transceiver 514, the baseband 516, or the DSP 518.

In one example of a scenario for setting the mode of the power amplifier504, the transceiver 514 receives a signal from, for example, theantenna 520 or the DSP 518. In response to receiving the signal, thetransceiver 514 can provide one or more signals to the mode selector540. Based on the one or more signals received from the transceiver 514,the mode selector 540 can configure the digital control interface 508 tooperate as either a serial interface or a GPIO interface. Further, thetransceiver 514 can provide one or more signals to the digital controlinterface 508, which processes the signals in serial mode or GPIO modebased on the mode specified by the mode selector 540. Based on theoutcome of processing the signals, the digital control interface 508 canprovide one or more mode setting signals to the power amplifiercontroller 506, which can set the mode of the power amplifier 504 basedon the mode setting signals. Alternatively, the digital controlinterface 508 may set the mode of the power amplifier 504.

In some implementations, the power amplifier 504 may include one or moreof the power amplifier controller 506, the digital control interface508, and the mode selector 540. For some implementations, the poweramplifier controller 506 may include one or more of the digital controlinterface 508 and the mode selector 540. Moreover, in some cases, thedigital control interface may include the mode selector 540. Further,the power amplifier module 502 may be a single component that includesthe functionality of the mode selector 540, the digital controlinterface 508, the power amplifier controller 506, and the poweramplifier 504. Alternatively, the power amplifier module 502 may includemultiple components that include the functionality of the mode selector540, the digital control interface 508, the power amplifier controller506, and the power amplifier 504. In yet other implementations, thewireless device 500 may include one or more components that include thefunctionality of the mode selector 540, the digital control interface508, the power amplifier controller 506, and the power amplifier 504.

Similar to the power amplifier module 102, the power amplifier module502 can receive power from a power supply 522. The power amplifiermodule 502 can then distribute the power to a number of componentsincluded in the wireless device 500 via, for example, the powerdistribution bus 524.

In certain embodiments, the power supply 522 includes combinationallogic and/or one or more processors that enable the power supply 522, insome cases, to configure one or more elements of the power amplifiermodule 502. For example, in some cases, the power supply 522 may provideone or more signals to the digital control interface 508 to enable thedigital control interface 508 to configure the power amplifier 504.Further, the power supply 522 may provide the signals to, for example,the digital control interface 508 based on the output of the poweramplifier 504 thereby creating a feedback loop between the poweramplifier module 502 and the power supply 522.

The wireless device 500 can include a number of additional components.At least some of these additional components may receive power via thepower distribution bus 524. For example, the wireless device 500 caninclude a digital to analog convertor (DAC) 526, a display processor528, a central processor 530, a user interface processor 532, an analogto digital convertor (ADC) 534, and memory 536. At least some of theadditional components may communicate with the digital control interface508 and may cause the digital control interface 508 to modify thesettings of the power amplifier module 502, the power amplifier 504,and/or the power amplifier controller 506. In addition, at least some ofthe additional components may communicate with the mode selector 540 andcause the mode selector 540 to select the operational mode of thedigital control interface 508.

Second Example of a Digital Control Interface

FIG. 6 illustrates an embodiment of a digital control interface 508 inaccordance with aspects of the present disclosure. In someimplementations, some or all of the embodiments described above withrespect to the digital control interface 108 and the digital controlinterface 200 may apply to the digital control interface 508.

The digital control interface 508 includes a serial interface 510, aGPIO interface 512, and a number of input pins. These input pins caninclude a VIO pin 604, a clock/mode pin 606, and a data/enable pin 608.

The VIO pin 604 may be configured to receive a signal setting thedigital control interface 508 to operate as either a serial interface ora GPIO interface. In the illustrated embodiment, the digital controlinterface 508 operates as a serial interface when the VIO pin 604receives a logic high signal and operates as a GPIO interface when theVIO pin 604 receives a logic low signal. However, in someimplementations, the digital control interface 508 can be configured tooperate as a serial interface when the VIO pin 604 receives a logic lowsignal and as a GPIO interface when the VIO pin 604 receives a logichigh signal. The logic low signal can be associated with any valuedefined to be low, such as 0 volts, −5 volts, or otherwise. Similarly,the logic high signal can be associated with any value defined to behigh, such as 0 volts, +5 volts, or otherwise. In some implementations,the logic low signal may be associated with connecting the VIO pin 604to ground. Similarly, in some cases, the logic high signal may beassociated with connecting the VIO pin 604 to a voltage source.

Further, the VIO pin 604 may be configured to provide power from a powersource, such as the power supply 522, to the serial interface core 602.Thus, in some embodiments, when the VIO pin 604 is set to logic low, oris grounded, the serial interface core 602 is not powered and thedigital control interface 508 is configured to function as a GPIOinterface. On the other hand, in some embodiments, when the VIO pin 604is set to logic high, or is connected, directly or indirectly, to apower source, the serial interface 602 is provided with power and thedigital control interface 508 is configured to function as a serialinterface. In some implementations, some or all of the embodimentsdescribed above with respect to the VIO pin 204 may apply to the VIO pin604.

The serial interface 510 may include a front end core, or a serialinterface core 602. Further, the serial interface 510 may include apower on reset 610, a pair of buffers 632 and 634, and a number of levelshifters 614. The GPIO interface 512 may include combinational logicblock 612, and a pair of level shifters 616 and 618. When the digitalcontrol interface 508 functions as a serial interface, the components ofthe serial interface 510 are active or operate to provide a serialinterface and one or more components of the GPIO interface 512 may notbe active. Similarly, when the digital control interface 508 functionsas a GPIO interface, the components of the GPIO interface 512 are activeor operate to provide a GPIO interface and one or more components of theserial interface 510 may not be active.

However, in certain embodiments, when the digital control interface 508functions as a serial interface, the digital control interface 508 mayuse one or more components of the GPIO interface 512 to facilitateproviding a serial interface, and thus, one or more components of theGPIO interface 512 may be active or operate to provide the serialinterface. Similarly, in certain embodiments, when the digital controlinterface 508 functions as a GPIO interface, the digital controlinterface 508 may use one or more components of the serial interface 510to facilitate providing a GPIO interface, and thus, one or morecomponents of the serial interface 510 may be active or operate toprovide the GPIO interface. For example, in some implementations, thecombinational logic block 612 may include a multiplexor that iscontrolled by the power on reset 610. Further, in this example, thecombinational logic block 612, based on the mode of operation of thedigital control interface 508, and therefore the value output by thepower on reset 610, may provide different signals to the level shifters616 and 618. Thus, in this example, although the power on reset 610 isgenerally part of the serial interface 510, the power on reset 610 mayfunction as part of the GPIO interface when the digital controlinterface is in GPIO interface mode. Similarly, in this example,although the combinational logic block 612 and the level shifters 616and 618 are generally part of the GPIO interface 512, one or more of thecombinational logic block 612 and the level shifters 616 and 618 mayoperate to help provide a serial interface when the digital controlinterface 508 is in serial interface mode.

The power on reset 610 may be implemented in hardware, software, or acombination of the two. Further, the power on reset 610 may beconfigured to facilitate resetting a serial interface core 602. In someembodiments, the power on reset 610 can serve as an inverted delayfunction. The inverted delay function is configured to providesufficient time for one or more logic blocks and/or one or moreregisters associated with the serial interface core 602 to be set to aknown condition or value when configuring the digital control interface508 as a serial interface. Although, in some cases, the length of timemay be application specific, in other cases the length of time may bebased on characteristics of the hardware design and/or implementation.For example, the amount of time required may depend on the clockfrequency, the size of the logic components, the type of componentsconnected, directly or indirectly, to the digital control interface 200,etc. Further, setting the logic blocks and/or registers to known valuesmay occur when initializing the serial interface core 602 or taking theserial interface core 602 out of a reset state.

In some implementations, the power on reset 610 may be configured toprovide a select signal to the combinational logic block 612. Forexample, assume that the digital control interface 508 is configured tooperate as a GPIO interface when the VIO pin 604 receives a logic lowsignal and as a serial interface when the VIO pin 604 receives a logichigh signal. Continuing this example, when the VIO pin 604 receives alogic low signal, the select signal provided by the power on reset 610may cause the combinational logic block 612 to output to the enablelevel shifter 616 and the mode level shifter 618 signals based on theinput to the data/enable pin 608 and the clock/mode pin 606respectively. For instance, the combinational logic block 612 may decodethe signals received from the clock/mode pin 606 and the data/enable pin608 and provide the decoded signals to the enable level shifter 616 andthe mode level shifter 618.

If, in this example, the VIO pin 604 receives a logic high signalinstead of the logic low signal, the select signal provided by the poweron reset 610 may cause the combinational logic block 612 to outputsignals based on signals received from the serial interface core 602 tothe enable level shifter 616 and the mode level shifter 618. In certainembodiments, the combinational logic block 612 may delay or otherwisemodify the signals received from data/enable pin 608 and the clock/modepin 606 or the serial interface core 602 before outputting the signalsto the level shifters 616 and 618.

In some cases, the power on reset 610 may be configured to place one ormore of the level shifters 614 into a default or reset state. This mayoccur, for example, when the serial interface core 602 is in a resetstate. In some designs, the power on reset 610 may be connected to adefault high pin associated with each level shifter configured to behigh during GPIO interface mode and to a default low pin associated witheach level shifter configured to be low during GPIO interface mode. Insome implementations, setting a level shifter 614 into a default statemay cause the level shifter 614 to output a value based on a defaultinput signal provided by the default pin 620. Although the default pin620 is illustrated as receiving a default input signal, in a number ofembodiments, the default pin 620 is tied to one of a default high and adefault low input. Thus, in some cases, the default value may bepre-configured, while in other cases, the default value may beapplication specific and may vary based on the configuration oroperation of the digital control interface 508 or the power amplifiermodule. It is possible in some designs that each level shifter 614 maybe associated with a different default value or signal. Alternatively,each level shifter 614 may be associated with the same default value orsignal.

Each of the level shifters 614 may be powered through a Vcc pin 624. Insome implementations, each level shifter 614 may be separately connectedto a power source. Alternatively, a single level shifter 614 may beconnected, directly or indirectly, to a power source, and the remaininglevel shifters 614 may obtain power by a connection to the level shifter614, or other component, that is connected to the power source. Further,the level shifters 616 and 618 may similarly each be connected to apower source, or may be connected to a level shifter or other componentthat can provide power to the level shifters 616 and 618. In certainembodiments, the level shifters 614, 616, and 618 are configured toadjust the voltage level of received signals and to output the modifiedsignals. Although not limited as such, the level shifters 614, 616, and618 may adjust the voltage level of the received signals tosubstantially match the voltage applied at the Vcc pin 624.

In some implementations, some or all of the embodiments described abovewith respect to the power on reset 210 may apply to the power on reset610. Similarly, in some implementations, some or all of the embodimentsdescribed above with respect to the level shifters 220 may apply to thelevel shifters 614. Further, in some implementations, some or all of theembodiments described above with respect to the level shifters 216 and218 may apply to the level shifters 616 and 618 respectively. Inaddition, some or all of the embodiments described above with respect tothe level shifter 300 may apply to the level shifters 614, 616, and 618.

The serial interface core 602 may generally include circuitry or logicthat enables the serial interface core to provide a serial interface. Insome embodiments, the serial interface core 602 can include a RFFE core(e.g. the RFFE core 202). Further, in some instances, the serialinterface core 602 can include some or all of the embodiments describedabove with respect to the RFFE core 202.

As with the RFFE core 202, the serial interface core 602 may include aset of registers (not shown). In certain situations, the set ofregisters may be set to unknown values. For example, when the wirelessdevice 500 is first powered, the set of registers may be set to unknownvalues. As a second example, in implementations where the VIO pin 604serves as both the power source for the serial interface core 602 andthe mode selector between serial interface mode and GPIO interface mode,the set of registers may be set to unknown values when the digitalcontrol interface 508 is first transitioned from a GPIO interface to aserial interface. To ensure that the registers are set to known valueswhen the serial interface core 602 is initially powered or taken out ofa reset state, the serial interface core 602 can be configured to setthe value of each of the set of registers to values provided by a set ofstrapped defaults 622. In certain implementations, the strapped defaults622 may be equivalent to the values provided to the default pins 620.

In certain embodiments, the serial interface core 602 may be configuredto receive a clock signal from the clock/mode pin 606. This clock signalmay be set to any frequency or signal shape based on the implementationof the serial interface core 602. In some implementations, the clocksignal may be a square wave with a frequency of 26 MHz or less. Further,the data interface of the serial interface core 602 may bebidirectional. Thus, the serial interface core 602 may receive data fromthe data/enable pin 808 at the Data In of the serial interface core 602.Similarly, the serial interface core 602 may provide data from the DataOut of the serial interface core 602 to the data/enable pin 608. Asillustrated in FIG. 6 by the buffers 632 and 634, both the data inputand the data output may be buffered. In some embodiments, the buffersmay be tri-state buffers. Further, the Output Enable of the serialinterface core 602 may be configured to control the buffers 632 and 634to enable both the Data Out and the Data In to share the same line toand from the data/enable pin 608. Thus, in some examples, when readingdata from the serial interface core 602, the buffer 632 enables dataflow, while the buffer 634 prevents data flow, or is set to highimpedance. Similarly, in some examples, when writing data to the serialinterface core 602, the buffer 634 enables data flow, while the buffer632 prevents data flow, or is set to high impedance.

The combinational logic block 612 generally includes any logic thatcauses the digital control interface 508 to provide an enable signal anda mode signal to the enable level shifter 616 and the mode level shifter618 respectively. In some embodiments, the combinational logic block 612includes logic that enables the decoding of a signal. The combinationallogic block 612 can then provide a decoded signal to one or both of thelevel shifters 616 and 618. In some instances, the combinational logicblock 612 can include some or all of the embodiments described abovewith respect to the combinational logic block 212.

In some implementations, the digital control interface 508 can performthe process 400 described above with respect to FIG. 4. In suchimplementations, operations associated with the RFFE core may instead beperformed by the serial interface core 602. For example, block 416 mayinclude placing the serial interface core 602 into a reset mode. As asecond example, block 432 may include providing serial interfaceregister values, or signals associated with registers of the serialinterface core 602, to the serial interface level shifters 614.

Example of a Combinational Logic Block

FIG. 7 illustrates an embodiment of a combinational logic block 612 inaccordance with aspects of the present disclosure. As described above,the combinational logic block 612 may be configured to output an enablesignal and a mode signal to the level shifters 616 and 618 respectively.Further, the combinational logic block 612 includes logic thatdetermines whether the enable and mode signals are based on inputsreceived from the serial interface core 602 or inputs received from theclock/mode pin 606 and data/enable pin 608. In some cases, when thedigital control interface 508 is operating as a GPIO interface, theenable signal and mode signal may be based on inputs received viaadditional logic or devices (not shown) that receive the input signalsfrom the clock/mode pin 606 and data/enable pin 608. Similarly, in somecases, when the digital control interface 508 is operating as a serialinterface, the enable signal and mode signal may be based on inputsreceived via additional logic or devices (not shown) that receive thesignals from the serial interface core 602. In some cases, theadditional logic or devices may process the signals before providing thesignals to the combinational logic block 612.

As illustrated in FIG. 7, the combinational logic block 612 includesmultiplexor 720 and multiplexor 722. The multiplexor 720 can provide theenable signal to the enable level shifter 616 and the multiplexor 722can provide the mode signal to the mode level shifter 618. Each of themultiplexors may be controlled by a reset signal received from the resetinput 710 to the combinational logic block 612. As described above, thereset signal may be received from the power on reset 610 and, in somecases, may be an inverted version of a signal received from the VIO pin604.

As previously described, in some embodiments, when the reset signalreceived at the reset input 710 to the combinational logic block 612 islogic high, or a ‘1’, the digital control interface 508 operates as aGPIO interface. In such cases, the multiplexor 720 outputs the signalreceived at the data/enable input 708, and the multiplexor 722 outputsthe signal received at the clock/mode input 706. As illustrated by thesmall squares, the inputs to the data/enable input 708 and theclock/mode input 706 may, in some cases, be received from thedata/enable pin 608 and the clock/mode pin 606 respectively, without anyintervening logic or components. In other embodiments, there may beadditional logic between the pins 606 and 608, and the inputs 706 and708 respectively.

In some embodiments, the combinational logic block 612 may include anAND gate 724 between the data/enable input 708 and the multiplexor 720,and/or an AND gate 726 between the clock/mode input 706 and themultiplexor 722. Although some embodiments include the AND gates, sincethe reset input 710 is logic high when selecting the input of thedata/enable input 708 and the clock/mode input 706, the output of themultiplexors does not change. In certain embodiments, the AND gates areincluded to reduce or eliminate digital noise caused by the frequency ofthe signals and/or the proximity of the signal paths to each other. Thedata and clock signals, in some cases, may be high speed digitalsignals, which in some implementations can be as fast as 26 MHz. Inother cases, the signals may be faster or slower than 26 MHZ and may beapplication dependent. The AND gates can be used to limit the number ofnodes that toggle at the rate of the signals thereby limiting the amountof clock energy that can degrade the RF performance aspects of one ormore devices in communication with the combinational logic block 612(e.g., the power amplifier controller 506, the power amplifier 504,etc.). In some cases, the AND gates may introduce a delay enablingsynchronization of one or more signals. In certain embodiments, the ANDgates may be optional.

Although the combinational logic block 612 of FIG. 7 includes AND gates,it is possible for the combinational logic block 612 to include othertypes of logic in addition to, or in place of the AND gates 724 and 726.For example, the combinational logic block 612 may include one or moreAND gates, NAND gates, inverters, OR gates, NOR gates, or XOR gatesbetween the inputs 708 and 706 and the multiplexors 720 and 722respectively.

When the reset signal received at the reset input 710 to thecombinational logic block 612 is logic low, or a ‘0’, the digitalcontrol interface 508 operates as a serial interface. In such cases, themultiplexor 720 outputs the signal received at the serial enable input702, and the multiplexor 722 outputs the signal received at the serialmode input 704.

Although FIG. 7 does not illustrate any additional logic than haspreviously been described, in some implementations, the combinationallogic block 612 may include additional logic components. For example,additional gates may be included to reduce noise, delay the timing ofsignals, or to store prior signals.

Third Example of a Digital Control Interface

FIG. 8 illustrates an embodiment of a digital control interface 800 inaccordance with aspects of the present disclosure. In some cases, thedigital control interface 800 may substitute for the digital controlinterface 508 (illustrated in FIG. 6) of the wireless device 500(illustrated in FIG. 5). In some implementations, some or all of theembodiments described above with respect to the digital controlinterface 108, the digital control interface 200, and the digitalcontrol interface 508 may apply to the digital control interface 800. Tosimplify discussion, elements in common between the digital controlinterface 508 and the digital control interface 800 are not redescribedbelow.

Advantageously, in certain embodiments, the digital control interface800 can support three modes when configured as a GPIO interface. In somecases, by enabling the digital control interface 800 to support threemodes when configured as a GPIO interface, the digital control interface800 is able to support more power amplifier modes than a signal controlinterface that uses separate mode and enable pins. Further, in somecases, the additional modes can supported without adding additional pininputs and without expanding the package size of the digital controlinterface. In some implementations, these advantages can be achieved byreplacing the data/enable pin 608 of the digital control interface 508with a pin that provides a second mode input and by modifying thecombinational logic block 612 to interpret the fourth available mode asa not enabled signal.

As illustrated in FIG. 8, the digital control interface 800 can includea clock/mode 0 pin 802 and a data/mode 1 pin 804. The pins 802 and 804can be configured similarly to the pins 606 and 608 of the digitalcontrol interface 508 respectively. However, when the digital controlinterface 800 is configured as a GPIO interface, the clock/mode 0 pin802 can provide a first mode signal to the combinational logic block 808and the clock/mode 1 pin 804 can provide a second mode signal to thecombinational logic block 808.

The GPIO interface 806 can include two mode level shifters, the mode 0level shifter 810 and the mode 1 level shifter 812. When the signaloutput by enable level shifter 616 indicates that the power amplifier504 should be enabled, the signals output by the two mode level shifterscan be used by the power amplifier controller 506 to set the level ofamplification of a signal received by the power amplifier 504. In someembodiments, the power amplifier 504 is enabled regardless of the outputof the enable level shifter 616. In some such cases, the output of theenable level shifter 616 may be used by the power amplifier controller506 to determine whether to adjust the mode of the power amplifier 504based on the outputs of the two mode level shifters 810 and 812.

As will be described in more detail below with respect to FIG. 9, thesignal supplied to the enable level shifter 616 may be based on thesignals received at the mode pins 802 and 804. Further, in some cases,the serial interface core 602 may provide three signal connections tothe combinational logic block 808, as illustrated in FIG. 8. In othercases, the serial interface core 602 may provide more or less signallines to the combinational logic block 808. In such cases, the signallines may be combined or split using one or more logic blocks and based,at least in part, on the number of level shifters receiving outputsignals from the combinational logic block 808.

Second Example of a Combinational Logic Block

FIG. 9 illustrates an embodiment of a combinational logic block 808 inaccordance with aspects of the present disclosure. In some embodiments,the combinational logic block 808 may include some or all of theembodiments as previously described with respect to the combinationallogic block 612.

Similar to the combinational logic block 612, the combinational logicblock 808 includes logic that determines whether the enable and modesignals are based on inputs received from the serial interface core 602or inputs received from the clock/mode 0 pin 802 and data/mode 1 pin804. In some cases, when the digital control interface 800 is operatingas a GPIO interface, the enable signal and the mode 0 and mode 1 signalsmay be based on inputs received via additional logic or devices (notshown) that receive the input signals from the clock/mode 0 pin 802 anddata/mode 1 pin 804. Similarly, in some cases, when the digital controlinterface 800 is operating as a serial interface, the enable signal andthe mode 0 and mode 1 signals may be based on inputs received viaadditional logic or devices (not shown) that receive the signals fromthe serial interface core 602. In some cases, the additional logic ordevices may process the signals before providing the signals to thecombinational logic block 808.

As illustrated in FIG. 9, the combinational logic block 808 includesthree multiplexors. The multiplexor 920 can provide the enable signal tothe enable level shifter 616. When the digital control interface 800 isconfigured as a serial interface, the multiplexor 920 outputs an enablesignal received from the serial interface core 602 via the serial enableinput 906. When the digital control interface 800 is configured as aGPIO interface, the multiplexor 920 outputs an enable signal that isbased on the logical OR of the signals received from the clock/mode 0input 902 and the data/mode 1 input 904. The logical OR may be obtainedvia the OR gate 930 illustrated in FIG. 9. However, other logicalequivalents are possible, such as by using a NOR gate and an inverter.

The multiplexor 922 can provide a first mode signal, or the mode 0signal, to the mode 0 level shifter 810. Similarly, the multiplexor 924can provide a second mode signal, or the mode 1 signal, to the mode 1level shifter 812. When the digital control interface 800 is configuredas a serial interface, the multiplexor 922 outputs a mode 0 signalreceived from the serial interface core 602 via the serial mode 0 input908. Likewise, when the digital control interface 800 is configured as aserial interface, the multiplexor 924 outputs a mode 1 signal receivedfrom the serial interface core 602 via the serial mode 1 input 910.

When the digital control interface 800 is configured as a GPIOinterface, the multiplexor 922 outputs the logical AND of the signalreceived at the clock/mode 0 input 902 and the reset signal received atthe reset input 912. Similarly, when the digital control interface 800is configured as a GPIO interface, the multiplexor 924 outputs thelogical AND of the signal received at the data/mode 1 input 904 and thereset signal received at the reset input 912. The logical ANDs may beobtained by the AND gates 926 and 928. However, other logicalequivalents are possible, such as by using a NAND gate and an inverter.As previously described with respect to FIG. 7, the use of the AND gates926 and 928 may reduce or eliminate digital noise.

Each of the multiplexors may be controlled by the reset signal receivedfrom the reset input 912. In other words, the select signal provided tothe multiplexors may be the reset signal. As described above, the resetsignal may be received from the power on reset 610 and, in some cases,may be an inverted version of a signal received from the VIO pin 604.When the reset signal is a logic ‘1’, the digital control interface 800is configured as a GPIO interface, and the multiplexor outputs thesignals as described above for GPIO interface mode. When the resetsignal is a logic ‘0’, the digital control interface 800 is configuredas a serial interface, and the multiplexor outputs the GPIO signals asdescribed above for serial interface mode.

As previously described, the digital control interface 800, using thecombinational logic 808 can provide three different modes to the poweramplifier controller 506 and/or the power amplifier 504 by using thevalues of the mode 0 pin 802 and the mode 1 pin 804 to determine whetherto output an enable signal instead or dedicating a separate pin to anenable control signal. When one of the three configured modes isselected, the combinational logic block 808 is configured to output anenable signal. When the fourth mode is selected, the combinational logicblock 808 is configured to output a not enabled signal. Table 1illustrates one non-limiting example for the outputs of thecombinational logic block 808 to the level shifters based on the valueof the mode pins when the digital control interface 800 is configured asa GPIO interface. The mode setting of Table 1 corresponds to the settingof the power amplifier controller 506 based on the output of the mode 0and mode 1 signals to the mode 0 and mode 1 level shifters 810 and 812respectively.

TABLE 1 MODE 0 MODE 1 ENABLE MODE SETTING 0 0 NO — 0 1 YES 1 1 0 YES 2 11 YES 3

In some embodiments, the digital control interface 800 can perform amodified version of the process 400. For example, in some cases, theblock 428 can include providing a first and second mode signal from aserial interface core to the first mode level shifter 810 and the secondmode level shifter 812, respectively. Further, the block 418, in somecases, includes providing a first mode signal from the clock/mode pin802 to the first mode level shifter 810 and a second mode signal fromthe data/mode pin 804 to the second mode level shifter 812. In certainembodiments, by providing two mode signals, the digital controlinterface 800 can provide three modes when operating as a GPIO interfaceinstead of two.

In some embodiments, the operation of the block 420 may be modified toprovide the first mode signal and the second mode signal from theclock/mode pin 802 and the data/mode pin 804, respectively, to thecombinational logic block 808. The combinational logic block 808 canthen determine whether to provide an enable signal to the enable levelshifter 616 based on the first and second mode signal thereby enablingthe digital control interface 800 to output an enable signal to thepower amplifier controller 506 without having a dedicated enable pin.Advantageously, in certain cases, by eliminating the need for an enablepin, the digital control interface can support more modes forconfiguring a power amplifier by repurposing the enable pin as a secondmode pin.

Additional Embodiments

In some embodiments, a digital control interface includes a voltageinput/output (VIO) pin configured to receive a VIO signal. Further, thedigital control interface can include a front end core configured toprovide a serial interface. The front end core may be in an active statewhen the VIO signal satisfies a first logic level and in an inactivestate when the VIO signal satisfies a second logic level. Further, thedigital control interface may be configured to provide a general purposeinput/output (GPIO) interface when the front end core is set to theinactive state. In addition, the digital control interface can include acombinational logic block configured to provide an enable signal to anenable level shifter and a mode signal to a mode level shifter.Moreover, the digital control interface can include a clock/mode pin anda data/enable pin. The clock/mode pin may be configured to provide aclock signal to the front end core when the front end core is set to anactive state and a mode signal to the combinational logic block when thefront end core is set to an inactive state. The data/enable pin may beconfigured to provide a data signal to the front end core when the frontend core is set to an active state and an enable signal to thecombinational logic block when the front end core is set to an inactivestate. Further, the digital control interface may include a power onreset configured to select, based on the VIO signal, a source of theenable signal and the mode signal provided to the enable level shifterand the mode level shifter respectively. With some implementations, thefront end core includes a radio frequency front end (RFFE) core.

In some cases, the data/enable pin is further configured to provide anaddress signal to the front end core when the front end core is set toan active state, the address signal associated with a register of thefront end core.

The digital control interface, in some implementations, may include aplurality of register level shifters. Each register level shifter of theplurality of register level shifters may be configured to receive aregister signal from the front end core and to output the registersignal thereby enabling a power amplifier to be configured based on theregister signal, the register signal associated with a value stored inone of a plurality of registers associated with the front end core. Insome cases, at least one register level shifter is further configured toreceive a default signal during a reset state. Further, the power onreset block may be further configured to place the at least one registerlevel shifter into the reset state. In some cases, the power on resetblock can be further configured to provide a delayed reset signal to thefront end core.

In certain embodiments, the digital control interface includes a firstbuffer and a second buffer. The first buffer may be connected betweenthe data/enable pin and an output port of the front end core and thesecond buffer may be connected between the data/enable pin and an inputport of the front end core. Further, the first buffer may be configuredto enable data to be read from the front end core and the second buffermay be configured to enable data to be provided to the front end core.Both the first buffer and the second buffer may be tri-state buffers. Insome designs, the connection between the first buffer and thedata/enable pin, and the connection between the second buffer and thedata/enable pin is a shared path. The first buffer and the second buffermay be further configured to prevent simultaneous data flow through thefirst buffer and the second buffer.

Some embodiments of the present disclosure may be configured toimplement a method for providing multiple control interfaces in adigital control interface that includes a front end core and acombinational logic block. The method can include receiving a VIO signalat a VIO input to the digital control interface and determining whetherthe VIO signal is logic high. In response to determining that the VIOsignal is logic high, the method can include configuring the digitalcontrol interface to function as a serial interface by providing a clocksignal from a clock input to the front end core, providing a data signalfrom a data input to the front end core, and selecting, at thecombinational logic block, a first enable signal and a first mode signalto output to an enable level shifter and a mode level shifter. Both thefirst enable signal and the first mode signal may be received from thefront end core. In response to determining that the VIO signal is logiclow, the method may include configuring the digital control interface tofunction as a general purpose input/output (GPIO) interface by providinga second enable signal from an enable input to the combinational logicblock, providing a second mode signal from a mode input to thecombinational logic block, and selecting, at the combinational logicblock, the second enable signal and the second mode signal to output tothe enable level shifter and the mode level shifter.

In some implementations, the method may include reconfiguring the frontend core from a reset state to an active state in response todetermining that the VIO signal is logic high. Reconfiguring the frontend core from the reset state to the active state can includeconfiguring a set of internal registers of the front end core to adefault value. With some implementations of the method, at least oneregister from the set of internal registers is configured to a differentdefault value than at least one other register from the set of internalregisters.

Further, the method can include providing an output of the enable levelshifter and an output of the mode level shifter to a power amplifiercontroller thereby enabling the power amplifier controller to configurea power amplifier based on the output of the enable level shifter andthe output of the mode level shifter. In addition, the method mayinclude placing the front end core into a reset mode in response todetermining that the VIO signal is logic low. Placing the front end coreinto the reset mode may include maintaining a default value at a set ofregister level shifters.

Certain aspects of the present disclosure can be included as part of apower amplifier. The power amplifier can include a digital controlinterface and a mode selector configured to provide a VIO signal to thedigital control interface. The VIO signal may be configured to set amode of the digital control interface. In certain implementations, thedigital control interface includes a voltage input/output (VIO) pinconfigured to receive the VIO signal and a front end core configured toprovide a serial interface. The front end core may be in an active statewhen the VIO signal satisfies a first logic level and in an inactivestate when the VIO signal satisfies a second logic level. The digitalcontrol interface can be configured to provide a general purposeinput/output (GPIO) interface when the front end core is set to theinactive state. Further, the digital control interface can include acombinational logic block configured to provide an enable signal to anenable level shifter and a mode signal to a mode level shifter and aclock/mode pin configured to provide a clock signal to the front endcore when the front end core is set to an active state and a mode signalto the combinational logic block when the front end core is set to aninactive state. Moreover, the digital control interface may include adata/enable pin configured to provide a data signal to the front endcore when the front end core is set to an active state and an enablesignal to the combinational logic block when the front end core is setto an inactive state. In some cases, the digital control interfaceincludes a power on reset block configured to select, based on the VIOsignal, a source of the enable signal and the mode signal provided tothe enable level shifter and the mode level shifter respectively. Insome implementations, the power amplifier control module also includes apower amplifier and a power amplifier controller configured to receivethe enable signal from the enable level shifter and the mode signal fromthe mode level shifter, and to provide a control signal to the poweramplifier based on the mode signal. The control signal may specify amode of operation of the power amplifier.

In some implementations of the power amplifier module, the data/enablepin is further configured to provide an address signal to the front endcore when the front end core is set to an active state. The addresssignal can be associated with a register of the front end core. Further,in some cases, the digital control interface includes a plurality ofregister level shifters. Each register level shifter of the plurality ofregister level shifters may be configured to receive a register signalfrom the front end core and to output the register signal therebyenabling a power amplifier to be configured based on the registersignal. The register signal may be associated with a value stored in oneof a plurality of registers associated with the front end core. Further,in some cases, at least one register level shifter is further configuredto receive a default signal during a reset state. The power on resetblock may be configured to place the at least one register level shifterinto the reset state.

In some embodiments, a digital control interface includes a voltageinput/output (VIO) pin configured to receive a VIO signal. The VIOsignal may correspond to one of a first logic level and a second logiclevel. Further, the digital control interface may include a clock/modepin configured to receive a first signal corresponding to one of thefirst logic level and the second logic level, and a data/mode pinconfigured to receive a second signal corresponding to one of the firstlogic level and the second logic level. In addition, the digital controlinterface may include a general purpose input/output (GPIO) interfacemodule and a serial interface module. In some cases, the GPIO interfacemodule includes an enable level shifter, a first mode level shifter, asecond mode level shifter, and a combinational logic block. Thecombinational logic block can be configured to provide an enable signalto the enable level shifter for output to a power amplifier controller.Further, the combinational logic block can be configured to provide afirst mode signal to the first mode level shifter for output to thepower amplifier controller and a second mode signal to the second modelevel shifter for output to the power amplifier controller. The enablesignal may correspond to an enable logic value when one or more of thefirst signal and the second signal correspond to the first logic leveland the VIO signal corresponds to the second logic level. Moreover, thefirst mode signal may correspond to the first signal and the second modesignal may correspond to the second signal when the VIO signalcorresponds to the second logic level. In some cases, the poweramplifier controller is configured to control a power amplifier based,at least in part, on the first mode signal and the second mode signal.Some implementations of the serial interface module include a serialinterface core and a reset logic block. The serial interface core can beconfigured to provide a serial interface when the VIO signal correspondsto the first logic level and the reset logic block can be configured toplace the serial interface core into a reset mode when the VIO signalcorresponds to the second logic level.

In some embodiments, the enable signal corresponds to a non-enabledlogic value when the first signal and the second signal each correspondto the second logic level and the VIO signal corresponds to the secondlogic level. Further, the enable signal may correspond to a serialenable value received from the serial interface core when the VIO signalcorresponds to the first logic value. In addition, the first mode signalmay correspond to a first serial mode signal received from the serialinterface core when the VIO signal corresponds to the first logic valueand the second mode signal may correspond to a second serial mode signalreceived from the serial interface core when the VIO signal correspondsto the first logic value.

With some implementations, the data/mode pin is further configured toprovide an address signal to the serial interface core when the VIOsignal corresponds to the first logic level. The address signal may beassociated with a register of the serial interface core. In addition,the clock/mode pin may be further configured to provide a clock signalto the serial interface core when the VIO signal corresponds to thefirst logic level.

The digital control interface, in some embodiments, includes a pluralityof register level shifters. Each register level shifter of the pluralityof register level shifters may be configured to receive a registersignal from the serial interface core and to output the register signalto the power amplifier controller. This enables, in some cases, thepower amplifier controller to configure the power amplifier based on theregister signal. The register signal can be associated with a valuestored in one of a plurality of registers associated with the serialinterface core.

In some embodiments, the serial interface module further includes afirst buffer and a second buffer. The first buffer can be configured toenable data to be read from the serial interface core and the secondbuffer configured to prevent data from being written to the serialinterface core when a buffer control signal is set to a first value.Further, the first buffer can be configured to prevent data from beingread from the serial interface core and the second buffer configured toenable data to be written to the serial interface core when the buffercontrol signal is set to a second value. In some cases, the buffercontrol signal is generated by the serial interface core.

Some embodiments of the present disclosure may be configured toimplement a method for providing multiple control interfaces in adigital control interface that includes a GPIO interface module and aserial interface module, which may include a serial interface core. Themethod can include receiving a VIO signal at a VIO input to the digitalcontrol interface and determining whether the VIO signal corresponds toa logic high value. In response to determining that the VIO signalcorresponds to the logic high value, the method can include configuringthe digital control interface to function as a serial interface byproviding a clock signal from a clock input to the serial interfacecore, providing a data signal from a data input to the serial interfacecore, and selecting, at a combinational logic block, a first enablesignal to output to an enable level shifter, a first mode signal tooutput to a first mode level shifter, and a second mode signal to outputto a second mode level shifter. The first enable signal, the first modesignal, and the second mode signal may each be received from a serialinterface core. In response to determining that the VIO signalcorresponds to a logic low value, the method may include configuring thedigital control interface to function as a general purpose input/output(GPIO) interface by providing a first input signal and a second inputsignal to the combinational logic block, and selecting, at thecombinational logic block, a second enable signal to output to theenable level shifter, a third mode signal to output to the first modelevel shifter, and a fourth mode signal to output to the second modelevel shifter. The second enable signal may be based on a logicaloperation of the first input signal and the second input signal.Further, the third mode signal may be based, at least in part, on thefirst input signal, and the fourth mode signal may be based, at least inpart, on the second input signal.

The method, in some cases, includes reconfiguring the serial interfacecore from a reset state to an active state in response to determiningthat the VIO signal corresponds to the logic high value. Reconfiguringthe serial interface core from the reset state to the active state caninclude configuring a set of internal registers of the serial interfacecore to a default value.

Further, the method can include providing an output of the enable levelshifter, an output of the first mode level shifter, and an output of thesecond mode level shifter to a power amplifier controller therebyenabling the power amplifier controller to configure a power amplifierbased on the output of the first model level shifter and the output ofthe second mode level shifter when the output of the enable levelshifter corresponds to an enabled value. Moreover, the method mayinclude placing the serial interface core into a reset mode in responseto determining that the VIO signal corresponds to the logic low value.Placing the serial interface core into the reset mode may includeloading a set of default values into a set of registers of the serialinterface core.

Certain aspects of the present disclosure can be included as part of apower amplifier. The power amplifier can include a digital controlinterface, a power amplifier, a power amplifier controller, and a modeselector configured to provide a VIO signal to the digital controlinterface. In some cases, the VIO signal is configured to set the modeof a digital control interface and may corresponding to one of a firstlogic level and a second logic level. The digital control interface mayinclude a voltage input/output (VIO) pin configured to receive the VIOsignal, a clock/mode pin configured to receive a first signalcorresponding to one of the first logic level and the second logiclevel, and a data/mode pin configured to receive a second signalcorresponding to one of the first logic level and the second logiclevel. Further, the digital control interface may include a generalpurpose input/output (GPIO) interface module, which may include anenable level shifter, a first mode level shifter, a second mode levelshifter, and a combinational logic block. In some cases, thecombinational logic block is configured to provide an enable signal tothe enable level shifter for output to the power amplifier controller.The combinational logic block may be further configured to provide afirst mode signal to the first mode level shifter for output to thepower amplifier controller and a second mode signal to the second modelevel shifter for output to the power amplifier controller. The enablesignal can correspond to an enable logic value when one or more of thefirst signal and the second signal correspond to a first logic level andthe VIO signal corresponds to the second logic level. In some cases, thefirst mode signal corresponds to the first signal and the second modesignal corresponds to the second signal when the VIO signal correspondsto the second logic level. In addition, the digital control interfacecan include a serial interface module, which may include a serialinterface core and a reset logic block. The serial interface core can beconfigured to provide a serial interface when the VIO signal correspondsto the first logic level and the reset logic block can be configured toplace the serial interface core into a reset mode when the VIO signalcorresponds to the second logic level. Further, the power amplifiercontroller can be configured to receive the enable signal from theenable level shifter, the first mode signal from the first mode levelshifter, and the second mode signal from the second mode level shifter.In addition, the power amplifier controller can control the poweramplifier by providing a control signal to the power amplifier based, atleast in part, on the first mode signal and the second mode signal. Thiscontrol signal may specify a mode of operation of the power amplifier.

In some embodiments, a wireless device may include a power amplifiermodule. The power amplifier module may include one or more of thepreviously described embodiments. Further, the wireless device caninclude a power supply configured to power the power amplifier moduleand a transceiver configured to provide a control signal to a modeselector of the power amplifier module.

In some embodiments, a digital control interface includes a voltageinput/output (VIO) pin configured to receive a VIO signal. Further, thedigital control interface may include a general purpose input/output(GPIO) interface module and a serial interface module. The GPIOinterface module can include an enable level shifter, a first mode levelshifter, a second mode level shifter, and a combinational logic block.The combinational logic block may be configured to provide an enablesignal to the enable level shifter for output to a power amplifiercontroller. The combinational logic block may further be configured toprovide a first mode signal to the first mode level shifter for outputto the power amplifier controller and a second mode signal to the secondmode level shifter for output to the power amplifier controller. Theserial interface module can include a serial interface core and a resetlogic block. The serial interface core can be configured to provide aserial interface when the VIO signal corresponds to a first logic level.Further, the reset logic block can be configured to place the serialinterface core into a reset mode when the VIO signal corresponds to asecond logic level. Moreover, the GPIO interface module can beconfigured to provide a GPIO interface when the VIO signal correspondsto the second logic level.

In certain implementations, the digital control interface may alsoinclude a clock/mode pin configured to receive a first signalcorresponding to one of the first logic level and the second logiclevel. Further, the digital control interface may include a data/modepin configured to receive a second signal corresponding to one of thefirst logic level and the second logic level. In some cases, the enablesignal may correspond to an enable logic value when one or more of thefirst signal and the second signal correspond to the first logic leveland the VIO signal corresponds to the second logic level. In addition,the first mode signal may correspond to the first signal and the secondmode signal may correspond to the second signal when the VIO signalcorresponds to the second logic level. In some embodiments, the poweramplifier controller is configured to control a power amplifier based,at least in part, on the first mode signal and the second mode signal.

TERMINOLOGY

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The term “coupled” is used to refer tothe connection between two elements, the term refers to two or moreelements that may be either directly connected, or connected by way ofone or more intermediate elements. Additionally, the words “herein,”“above,” “below,” and words of similar import, when used in thisapplication, shall refer to this application as a whole and not to anyparticular portions of this application. Where the context permits,words in the above Detailed Description using the singular or pluralnumber may also include the plural or singular number respectively. Theword “or” in reference to a list of two or more items, that word coversall of the following interpretations of the word: any of the items inthe list, all of the items in the list, and any combination of the itemsin the list.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

Conditional language used herein, such as, among others, “can,” “might,”“may,” “e.g.,” and the like, unless specifically stated otherwise, orotherwise understood within the context as used, is generally intendedto convey that certain embodiments include, while other embodiments donot include, certain features, elements and/or states. Thus, suchconditional language is not generally intended to imply that features,elements and/or states are in any way required for one or moreembodiments or that one or more embodiments necessarily include logicfor deciding, with or without author input or prompting, whether thesefeatures, elements and/or states are included or are to be performed inany particular embodiment.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A power amplifier module comprising: a poweramplifier configured to amplify a radio frequency (RF) signal; a poweramplifier controller; and a digital control interface configured toprovide a set of control signals to the power amplifier controller, thepower amplifier controller configured to control the power amplifierbased on the set of control signals, the digital control interfaceincluding a voltage input/output (VIO) pin, a serial interface module,and a general purpose input/output (GPIO) interface module, the serialinterface module including a serial interface core configured to providea serial interface when active, the serial interface core activated inresponse to a first voltage signal received by the VIO pin, and the GPIOinterface module configured to provide a GPIO interface responsive to asecond voltage signal received by the VIO pin, the serial interface coredeactivated in response to the second voltage signal.
 2. The poweramplifier module of claim 1 wherein the serial interface module furtherincludes a reset module configured to deactivate the serial interfacecore in response to the second voltage signal, the reset module furtherconfigured to perform an inverted delay function enabling a register ofthe serial interface core to be configured with a value before theserial interface core completes activation.
 3. The power amplifiermodule of claim 1 wherein the digital control interface further includesa combinational logic block configured to select from a first set ofsignals received from the serial interface core and a second set ofsignals received from a set of input pins based on a control signalreceived from a reset module.
 4. The power amplifier module of claim 1wherein the digital control interface further includes a first set oflevel shifters configured to modify a voltage level of a first set ofsignals received from the serial interface core and a second set oflevel shifters configured to modify a voltage level of a second set ofsignals received from a combinational logic block.
 5. The poweramplifier module of claim 4 wherein the set of control signals includesat least one of the first set of signals and the second set of signals.6. The power amplifier module of claim 1 wherein the digital controlinterface further includes a first tri-state buffer for reading datafrom the serial interface core and a second tri-state buffer for writingdata to the serial interface core, the first tri-state buffer set to ahigh-impedance by the serial interface core when data is written to theserial interface core and the second tri-state buffer set to ahigh-impedance by the serial interface core when data is read from theserial interface core.
 7. The power amplifier module of claim 1 furthercomprising a mode selector configured to provide one of the firstvoltage signal and the second voltage signal to the VIO pin.
 8. Awireless device comprising: an antenna configured to transmit andreceive wireless signals; and a power amplifier module including a poweramplifier configured to amplify a radio frequency (RF) signal, a poweramplifier controller, and a digital control interface configured toprovide a set of control signals to the power amplifier controller, thepower amplifier controller configured to control the power amplifierbased on the set of control signals, the digital control interfaceincluding a voltage input/output (VIO) pin, a serial interface module,and a general purpose input/output (GPIO) interface module, the serialinterface module including a serial interface core configured to providea serial interface when active, the serial interface core activated inresponse to a first voltage signal received by the VIO pin, and the GPIOinterface module configured to provide a GPIO interface responsive to asecond voltage signal received by the VIO pin, the serial interface coredeactivated in response to the second voltage signal.
 9. The wirelessdevice of claim 8 wherein the serial interface module further includes areset module configured to deactivate the serial interface core inresponse to the second voltage signal.
 10. The wireless device of claim8 wherein the power amplifier module further includes a mode selectorconfigured to cause the digital control interface to provide one of theserial interface and the GPIO interface.
 11. A digital control interfacecomprising: a voltage input/output (VIO) pin; a serial interface moduleincluding a serial interface core configured to provide a serialinterface when active, the serial interface core activated in responseto a first voltage signal received by the VIO pin; and a general purposeinput/output (GPIO) interface module configured to provide a GPIOinterface responsive to a second voltage signal received by the VIO pin,the serial interface core deactivated in response to the second voltagesignal.
 12. The digital control interface of claim 11 wherein the serialinterface module further includes a reset module configured todeactivate the serial interface core in response to the second voltagesignal.
 13. The digital control interface of claim 12 wherein the resetmodule is further configured to perform an inverted delay functionenabling a register of the serial interface core to be configured with avalue before the serial interface core completes activation.
 14. Thedigital control interface of claim 11 wherein the serial interfacemodule and the GPIO interface module share at least one functionalblock.
 15. The digital control interface of claim 11 further comprisinga combinational logic block configured to select from a first set ofsignals received from the serial interface core and a second set ofsignals received from a set of input pins based on a control signalreceived from a reset module.
 16. The digital control interface of claim11 further comprising a set of level shifters configured to modify avoltage level of a set of signals received from the serial interfacecore.
 17. The digital control interface of claim 11 further comprising aset of level shifters configured to modify a voltage level of a set ofsignals received from a combinational logic block.
 18. The digitalcontrol interface of claim 11 further comprising a first tri-statebuffer for reading data from the serial interface core and a secondtri-state buffer for writing data to the serial interface core, thefirst tri-state buffer set to a high-impedance when writing data to theserial interface core and the second tri-state buffer set to ahigh-impedance when reading data from the serial interface core.
 19. Thedigital control interface of claim 18 wherein the first tri-state bufferand the second tri-state buffer are controlled by the serial interfacecore.
 20. The digital control interface of claim 11 wherein at least oneof the serial interface module and the GPIO module is configured tooutput a set of control signals to be provided to a power amplifiercontroller for configuring a power amplifier.